Curving and Changing Heightfield

[|DEATH|Ryan]

I am having some troubles performing height field manipulations in AssaultCube mapping. I'm sorry to have to post a thread about this, but I really need to know how to do this. I have went through the IRC many times, and figured I should ask here. So, how do I manipulate the height field like they did in DESERT, and DOUZE? I have posted a picture of what I'm talking about from the map ac_douze below-



Thanks a lot for the help guys,
|DEATH|Ryan